The primary objective of the study is to study how the drug, amiloride ( a water pill), affects the exretion of sodium and potassium in the urine in relation to the urinary excretion of the drug in healthy volunteers. We hypothesize that it is the urinary exretion of amiloride affects the diuretic response to the drug in a dose dependent and reproducible manner and that each individual has a unique sensitivity to this drug.